1. Field of the Invention
The present invention relates to a method for producing thermoelectric elements and more particularly to a method for efficiently producing thermoelectric elements having excellent thermoelectric characteristics by controlling the particle diameter of the metal and metal alloy as the raw material.
2. Description of the Related Arts
In recent years, thermoelectric elements to be used in thermoelectric generation utilizing the Seebeck effect have been expected to be put into practice in various fields, and for production of, such thermoelectric elements, various methods have been proposed. A typical method is such that mechanically ground metal and metal alloy are used as the raw material, and they are molded by compressing by the use of, e.g., a press, sintered and then subjected to thermal treatment to produce a thermoelectric element having a predetermined shape.
The thermoelectromotive force of a thermoelectric element obtained by the above conventional method is not always sufficiently high and, therefore, it has been desired to develop a thermoelectric element having a high thermoelectromotive force.
Moreover, since the above mechanically ground metal and metal alloys have a large particle diameter and are not uniform in shape, the above conventional method has problems in that the sintering temperature is high, the sintering density after molding is not increased, and intergranular controlling is difficult.